JP2012211090A - Porous polyamide microparticles for cosmetic composition, and cosmetic composition containing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide porous polyamide microparticles for a cosmetic composition and a cosmetic composition containing the same, which, when applied to the skin, are superior in optical transparency and light scattering, have high soft-focus performance, and are capable of not only imparting a translucent effect but also suppressing a second aggregation during dry periods, and feel slippery and agreeable; and to provide a cosmetic composition containing the microparticles.SOLUTION: Disclosed are the porous polyamide microparticles for the cosmetic composition, which consist of a crystal structure wherein a crystalite size is 12 nm or more in terms of wide angle x-ray analysis and a degree of crystallinity is 50% in terms of DSC. Furthermore, disclosed is the cosmetic composition characterized by containing the porous polyamid microparticles and a cosmetic base.

Description

  The present invention includes porous polyamide fine particles for cosmetic compositions having excellent light transmission and light scattering properties, high soft focus properties, transparency, good slip and touch when applied to the skin, and the like Related to a cosmetic composition.

  Cosmetic compositions containing porous polyamide fine particles are excellent in light transmittance and light scattering properties, have high soft focus properties, and absorb sebum and sweat. For example, Patent Documents 1 and 2 disclose cosmetic compositions containing porous polyamide fine particles having a number average particle diameter of 1 to 30 μm and a particle diameter distribution of 1 to 1.5, which are substantially spherical, cylindrical, or dumbbell-shaped. Has been. In particular, in the dispersion solution, it is shown that the light scattering property of the dumbbell-shaped particles is higher than that of the spherical shape.

WO2004-043411 JP 2005-239575 A

  However, since the porous polyamide fine particles have a large number of pores as compared with ordinary true spherical particles, the specific surface area is large and the surface energy as the particles is large, so that secondary aggregation tends to occur during drying. For this reason, in the preparation formulated as a cosmetic raw material, if the aggregation of the particles is not completely loosened, the slip and the touch may be deteriorated. In particular, particles having a spherulite structure, such as dumbbell-shaped, cylindrical, and jade (C-type) particles, are more intensive in secondary aggregation than substantially spherical particles due to their shapes, which causes problems such as slip and tactile sensation. ing. Therefore, in order to improve these, the surface of the prepared particles was subjected to a silicone surface treatment by an existing method to improve the tactile sensation. However, it is difficult to solve the agglomeration once formed by the post-processing method.

  Therefore, the present invention, when applied to the skin, is excellent in light transmission and light scattering properties, has high soft focus properties and imparts a transparent feeling, suppresses secondary agglomeration during drying, and has slipperiness and tactile sensation. An object of the present invention is to provide a good porous polyamide fine particle for a cosmetic composition and a cosmetic composition containing the same.

  In order to achieve the above object, the inventors of the present invention have made extensive studies, and as a result, by using porous polyamide fine particles having a spherulite structure and having a crystallite size and a crystallinity adjusted, The present inventors have found that a cosmetic composition having excellent properties and light scattering properties, high soft focusability, imparting a transparent feeling, suppressing secondary agglomeration at the time of drying, and having good slip and feel can be produced. That is, the present invention relates to a porous polyamide fine particle for a cosmetic composition characterized by having a spherulite structure, a crystallite size by wide-angle X-ray analysis of 12 nm or more, and a crystallinity by DSC of 50% or more. is there.

  In addition, the present invention is a cosmetic composition comprising the above-described porous polyamide fine particles for a cosmetic composition and a cosmetic base material.

  As described above, according to the present invention, when applied to the skin, it is excellent in light transmission and light scattering properties, has a high soft focus property, imparts a transparent feeling, and suppresses secondary aggregation during drying. It is possible to provide porous polyamide fine particles for a cosmetic composition having good sliding and tactile sensation, and a cosmetic composition containing the same.

SEM image of porous polyamide fine particles obtained in Example 1 Measurement results of light scattering characteristics of each particle SEM image of porous polyamide fine particles obtained in Comparative Example 2 SEM image of porous polyamide fine particles obtained in Example 2 SEM image of porous polyamide fine particles obtained in Comparative Example 3

  In the cosmetic composition according to the present invention, the cohesiveness of the porous polyamide fine particles to be blended is improved, so that the tactile sensation and slip are very good. Moreover, since the crystallite size is larger than that of existing particles and the degree of crystallinity is high, the light scattering property is further improved, and the soft focus property as a cosmetic composition is further improved.

  The porous polyamide fine particles for a cosmetic composition according to the present invention are manufactured by a method using temperature-induced phase separation, which will be described later, and unlike a conventional method, a high-temperature polyamide solution and a low-temperature non-solvent are added in a short time. Addition, stirring, and mixing make the temperature in the system uniform in a very short time. For this reason, precipitation from a uniform polyamide solution with a lowered temperature is performed from a state in which the solution temperature in a supersaturated state is uniform in the system, and nucleation and nucleation progress almost simultaneously throughout the system. By controlling the temperature of the mixed solution and the polyamide concentration to control the nucleation and nucleation rate, a substantially spherical spherulite structure, which is peculiar to polyamide, or a partially deficient spherulite structure (C-type, jade-shaped) Furthermore, porous fine particles having a deficient axial spherulite structure (dumbbell shape, drum shape, cylindrical shape), a large crystallite size, and a high degree of crystallinity can be obtained. Further, the particle diameter and the particle shape are very uniform.

  The porous polyamide fine particles for cosmetic composition according to the present invention preferably have a crystallite size of 12 nm (nanometers) or more determined from wide-angle X-ray diffraction. Even if the crystallite size is less than 12 nm, if it has a porous structure, it has light scattering performance, but if it is larger than 12 nm, the light scattering property is further enhanced and the soft focus property is improved. preferable.

  The crystallinity measured by DSC is preferably 50% or more. The crystallinity of the porous polyamide fine particles can be determined by X-ray analysis, by DSC measurement, or by density. The DSC measurement method is preferred. The degree of crystallinity of the polyamide crystallized from the ordinary melt is at most about 30%. The porous polyamide fine particles for a cosmetic composition according to the present invention are preferable because the crystallinity is 50% or more, so that the light scattering property is increased and the soft focus property is improved. If the degree of crystallinity is low, the contrast of the difference in refractive index between the particles and the substrate is lowered, and the light scattering performance is lowered.

  Furthermore, the sphere equivalent number average particle diameter is preferably 1.0 to 30 μm, and more preferably 1.0 to 20 μm. When the sphere equivalent number average particle diameter is smaller than 1.0 μm, even if polyhydric alcohol is present in the fine particles, secondary aggregation often occurs, and handling operation becomes worse. When it is larger than 30 μm, when it is used as a cosmetic composition, roughness is generated, which is not preferable.

  Moreover, the porous polyamide fine particles for a cosmetic composition according to the present invention have a porous structure. The porous structure is also preferable because the multiple scattering effect increases, the light diffusion ability tends to increase, and the soft focus effect improves.

  Further, the porous polyamide fine particles for cosmetic composition according to the present invention have a spherical or substantially spherical spherulite structure, a spherulite structure having a bulge on one side and a defect on the other side (for example, C-shaped, It is preferable that the shape is a ball shape) or an axial spherulite structure (dumbbell shape, drum shape, cylindrical shape). The spherulite structure can be determined by observing the cross section of the particle with a scanning or transmission electron microscope and determining whether or not the polyamide fibrils grow radially from the vicinity of the central core. In the present invention, the single particle itself may have the spherulite structure as a whole or locally. "Single particles themselves have a global or local spherulitic structure" means that polyamide fibrils grow three-dimensionally or radially from single or multiple cores near the center of a single particle. The term “local” means that the particle has a part of the structure. By having the spherulite structure, the light scattering effect and the light transmittance are increased.

  When used in a cosmetic composition, preferably 70% or more, more preferably 80% or more, and still more preferably 90% or more of the entire porous polyamide fine particles have the above spherulite structure. . If the spherulite structure is less than 70%, the light scattering ability and the light transmittance are lowered, which is not preferable. In the present invention, particles having various structures may be mixed depending on applications.

BET specific surface area of a cosmetic composition for porous polyamide fine particles according to the present invention, preferably, 0.1~80m ² / g, more preferably, 1 to 50 m ² / g, more preferably, 3~30m ² / g. When the specific surface area is lower than 0.1 m ² / g, the porous property of the obtained porous fine particles is lowered and the light scattering property is deteriorated. Moreover, when larger than 80 m < ² > / g, it will become easy to aggregate.

  The average pore diameter is preferably 0.01 to 0.5 μm, more preferably 0.01 to 0.3 μm. When the average pore diameter is smaller than 0.01 μm, the porosity is lowered. When it is larger than 0.5 μm, the mechanical strength of the obtained fine particles may be lowered.

  Furthermore, the porosity index (RI) is preferably 5 to 100. Here, the porosity index (RI) is defined as the ratio of the specific surface area of the porous spherical fine particles to the specific surface area of the smooth spherical particles having the same diameter. If the porosity index is less than 5, it is not preferable because the carrying function and adsorption function as porous fine particles are inferior. When the porosity is greater than 100, it becomes difficult to handle as a powder.

  The porous polyamide fine particles for cosmetic compositions according to the present invention have a ratio of volume average particle diameter (or volume reference average particle diameter) to number average particle diameter (or number reference average particle diameter) of 1 in the sphere equivalent particle diameter distribution. It is preferable that it is -2.5, and it is further more preferable that it is 1-1.5. When the ratio of the volume average particle diameter to the number average particle diameter (particle size distribution index PDI) is larger than 2.5, the handling as a powder becomes worse.

  Next, a method for producing porous polyamide fine particles for a cosmetic composition according to the present invention will be described. The porous polyamide fine particles used in the cosmetic composition according to the present invention are produced by a method utilizing temperature-induced phase separation. For example, a polyamide used as a raw material is mixed with a solvent (A), and then heated to create a uniform solution. In order to rapidly and uniformly cool the entire polyamide solution to a predetermined temperature, a low-temperature solvent (B) Can be produced by adding the mixture with stirring within a predetermined time, and then allowing to stand. At that time, it is most important to stir and mix the two liquids in as short a time as possible, to homogenize them before starting the precipitation (white turbidity), and to stop the stirring and allow the precipitation to proceed under static conditions.

Examples of the polyamide used as a raw material for the porous polyamide fine particles include those obtained by ring-opening polymerization of cyclic amide, polycondensation of amino acids, polycondensation of dicarboxylic acid and diamine, and the like. Examples of raw materials used for ring-opening polymerization of cyclic amides include ε-caprolactam, ω-laurolactam, and the like, and raw materials used for polycondensation of amino acids include ε-aminocaproic acid, ω-aminododecanoic acid, ω- Examples of the raw material used for polycondensation of dicarboxylic acid and diamine include dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, 1,4-cyclohexyldicarboxylic acid, and derivatives thereof, ethylenediamine, hexa Examples include diamines such as methylene diamine, 1,4-cyclohexyl diamine, pentamethylene diamine, and decamethylene diamine.
These polyamides may be further copolymerized with a small amount of an aromatic component such as terephthalic acid, isophthalic acid, and m-xylylenediamine.

  Specific examples of polyamides include polyamide 6, polyamide 46, polyamide 66, polyamide 610, polyamide 612, polyamide 11, polyamide 12, polyamide 6/66, polynonamethylene terephthalamide (polyamide 9T), polyhexamethylene adipa. Polyamide / polyhexamethylene terephthalamide copolymer (polyamide 66 / 6T), polyhexamethylene terephthalamide / polycaproamide copolymer (polyamide 6T / 6), polyhexamethylene adipamide / polyhexamethylene isophthalamide copolymer (polyamide 66 / 6I) ), Polyhexamethylene isophthalamide / polycaproamide copolymer (polyamide 6I / 6), polydodecamide / polyhexamethylene terephthalamide copolymer (polyamide 12 / T), polyhexamethylene adipamide / polyhexamethylene terephthalamide / polyhexamethylene isophthalamide copolymer (polyamide 66 / 6T / 6I), polyhexamethylene terephthalamide / polyhexamethylene isophthalamide copolymer (polyamide 6T / 6I), Examples thereof include polyhexamethylene terephthalamide / poly (2-methylpentamethylene terephthalamide) copolymer (polyamide 6T / M5T), polyxylylene adipamide (polyamide MXD6), and mixtures or copolymer resins thereof. Among these, polyamide 6, polyamide 46, polyamide 66, polyamide 610, polyamide 612, polyamide 11, polyamide 12, or polyamide 6/66 copolymer resin is preferable, and polyamide 6 is particularly preferable from the viewpoint of material handleability.

  The molecular weight of the polyamide is preferably 2,000 to 100,000, more preferably 5,000 to 40,000. If the molecular weight of the polyamide is too small, the conditions for forming the porous polyamide fine particles are narrowed, making the production difficult. On the other hand, if the molecular weight of the polyamide is too large, primary aggregates are easily formed during production, which is not preferable.

  The solvent (A) is preferably a solvent that acts as a good solvent at a high temperature and a non-solvent at a low temperature with respect to the raw material polyamide, and examples thereof include polyhydric alcohols. Specifically, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 2,3-butanediol, 1,4-butanediol, glycerin, propylene glycol, dipropylene And glycol, 1,5-pentanediol, hexylene glycol and the like. These solvents may be used alone or in combination.

  An inorganic salt may be added to the solvent (A) in order to lower the dissolution temperature in order to promote dissolution, and examples of the inorganic salt include calcium chloride and lithium chloride. The above is not limited as long as the metal salt is an inorganic salt that acts on the hydrogen bond portion of the polyamide to promote dissolution.

  The temperature at which the polyamide is dissolved is preferably 10 to 100 ° C. higher than the temperature at which the polyamide starts to dissolve in the solvent (A) (hereinafter referred to as “phase separation temperature”). When dissolving, sealing the inside of the system with an inert gas such as nitrogen gas is preferable because the polyamide is less likely to deteriorate.

  The concentration of the polyamide uniform solution is preferably 0.1 to 30% by weight. If it is lower than 0.1% by weight, the productivity of the particles becomes low. If it is higher than 30% by weight, polyamide that cannot be partially dissolved may remain in the solution, and uniform fine particles may not be obtained.

  In the present invention, the entire polyamide solution is rapidly and uniformly cooled to a predetermined temperature by mixing the low-temperature solvent (B) with the homogeneous polyamide solution. The solvent (B) that can be used here is not limited as long as it acts as a non-solvent for polyamide at least at a low temperature and has high compatibility with the solvent (A). In the case of a composition or a mixed solution, the same composition is more preferable. In the case of different components and compositions, when collecting the particles and then reusing the solvent, a lot of labor may be required for fractional collection and the like.

  As said solvent (B) which can be used by this invention, the polyhydric alcohol similar to a solvent (A), and mixtures thereof are mentioned. Specifically, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 2,3-butanediol, 1,4-butanediol, glycerin, propylene glycol, dipropylene And glycol, 1,5-pentanediol, hexylene glycol and the like. These may be used alone or in combination.

  The temperature at which the polyamide solution is cooled and crystallized is preferably 20 to 80 ° C. lower than the phase separation temperature of the polyamide solution, more preferably 30 to 70 ° C., and most preferably 40 to 60 ° C. When the crystallization temperature is within 20 ° C. from the phase separation temperature, since the degree of supersaturation is low, it takes a long time for the polyamide to start and finish, so that a massive precipitate or an aggregate of particles is obtained. It is not preferable. On the other hand, when the temperature is lower than 80 ° C., the polyamide starts to precipitate due to a local decrease in temperature before the two liquids are uniformly stirred and mixed, resulting in non-uniform particles and aggregates.

  The temperature and amount of the solvent (B) used for cooling are determined by the temperature and volume of the polyamide solution to be cooled. The temperature difference between the solution and the non-solvent used for cooling is preferably within 150 ° C. When the temperature difference is larger than 150 ° C., the precipitation of polyamide starts during the addition of the non-solvent, and aggregation or the like occurs, which is not preferable. The final polyamide concentration after mixing the two liquids is preferably 15% by weight or less. If the polyamide concentration at the time of precipitation is too high, the particles are aggregated. In severe cases, the solution may solidify, which is not preferable.

  For mixing the high temperature polyamide solution and the low temperature solvent (B), the low temperature solvent (B) may be added to the high temperature polyamide solution, or the high temperature polyamide solution is added to the low temperature solvent (B). However, it is necessary to stir until the two liquids are uniform. The stirring time is most preferably within 3 minutes, preferably within 2 minutes, and more preferably within 1 minute. Whether or not the two liquids are sufficiently mixed can be determined by observing the concentration fluctuation due to the difference in refractive index between the two liquids or by keeping the temperature of the liquid mixture constant within ± 1 ° C.

  Stirring is not particularly limited in shape and apparatus as long as it is a commonly used stirring blade. Further, the rotational speed of the stirring blade is not particularly limited as long as the mixed solution becomes uniform in a short time. In addition, it is preferable to equip with a facility such as a baffle plate that enhances the stirring effect more uniformly in a shorter time.

  After the two liquids become uniform, stirring is preferably stopped and allowed to stand. If the stirring is continued even after the polyamide starts to precipitate, the shape of the obtained particles is not preferable because the shape of the particles varies in an incomplete shape, aggregation occurs, and the particle size distribution is widened. The baffle plate is preferable because the flow rate of the liquid after stopping stirring is stopped in a short time. It is preferable to hold the standing time until the precipitation is completed, specifically 5 minutes to 240 minutes are preferable, and 10 minutes to 120 minutes are more preferable.

  Further, after cooling to a predetermined temperature, it is preferable to deposit polyamide while maintaining the temperature. If the temperature of the cooled polyamide solution is changed, massive precipitates or aggregates of particles may be generated or the particle size distribution may be widened, which is not preferable.

  The porous polyamide fine particles prepared by the above method can be solid-liquid separated by a method such as decantation, filtration or centrifugation.

  Further, in the above method, the prepared porous polyamide fine particles can be washed with a low-viscosity solvent, which is a non-solvent of polyamide, near normal temperature in order to remove the non-solvent adhering to the surface. Examples of these solvents include compounds selected from the group consisting of aliphatic alcohols, aliphatic or aromatic ketones, aliphatic or aromatic hydrocarbons, and water. Examples of the aliphatic alcohol include monovalent aliphatic alcohols having 1 to 3 carbon atoms such as methanol, ethanol, 1-propanol, and 2-propanol. Examples of aliphatic ketones include acetone and methyl ethyl ketone. Examples of aromatic ketones include acetophenone, propiophenone, and butyrophenone. Examples of aliphatic hydrocarbons include heptane, hexane, octane, and n-decane. Examples of aromatic hydrocarbons include toluene and xylene.

  The separated and washed porous polyamide fine particles can be finally made into a dry powder through a drying step. As a drying method, general-purpose powder drying methods such as vacuum drying, constant temperature drying, spray drying, freeze drying, and fluidized tank drying can be used.

  The amount of residual polyhydric alcohol in the dry powder is preferably less than 10,000 ppm. If it is 10000 ppm or more, moisture in the air is likely to be taken in by residual polyhydric alcohol, and the particles themselves are liable to cause secondary agglomeration, resulting in a feeling of smoothness and a feeling of stickiness.

  Next, the cosmetic composition according to the present invention will be described. The cosmetic composition according to the present invention contains the above porous polyamide fine particles and a cosmetic base material, and can be used for various cosmetics such as foundations, lip balms, eye shadows, and therapeutic cosmetics depending on other components. Typical cosmetic compositions include liquids such as emulsions, pastes, or powders that can be easily applied to the skin.

  The cosmetic base means a component for maintaining the dosage form of the cosmetic composition. In the present invention, the cosmetic base material is not particularly limited, and a known base material can be appropriately used depending on the purpose. For example, water-soluble base materials such as glycerin, ethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol, sorbitol, various fatty acids, fatty acid alcohols, synthetic oils and fats such as waxes (for example, beeswax) and derivatives thereof , Oily base materials such as various vegetable oils, natural oils (for example, coconut oil) and fats and oils, water base materials such as water and various alcohols (for example, ethanol), liquid base materials such as various emulsion base materials, matte effect and glazing effect, Examples thereof include inorganic powders such as talc and clay, organic powders, fibrous powders, paste-like bases, mixed bases thereof, and the like, which have a sweat removing effect and other anti-peeling effects.

  Further, the cosmetic composition according to the present invention may contain an appropriate amount of a fragrance, an inorganic pigment, a dispersant, a preservative, an antioxidant, or the like, if necessary.

  The cosmetic composition according to the present invention may further comprise a cleaning agent, a moisturizing agent, a softening agent, an astringent, an ultraviolet absorber, an ultraviolet scattering agent, a coloring agent, a deodorant, a thickener, and a pH adjuster as necessary. A sequestering agent, a cell activator, a blood circulation promoter, a whitening agent, a sebum inhibitor, a bactericidal agent, an anti-inflammatory agent, an antiperspirant, and the like can be added.

  For example, when the cosmetic composition according to the present invention is used in a foundation, it preferably contains 10 to 300 parts by weight of a liquid base material with respect to 100 parts by weight of porous polyamide fine particles. As the liquid substrate, an oily substrate or latex (emulsion substrate) is preferable, and volatile or non-volatile silicone oil, liquid paraffin, vegetable oil, wax, glycerin, ethylene glycol and the like are preferable. Moreover, when using for foundation, it is preferable to contain 1-10 weight% of porous polyamide fine particles, and 1-15 weight% of inorganic fillers, and especially 2-9 weight% of porous polyamide particle microparticles and inorganic filler 1 It is preferable to contain 15 weight%. Examples of the inorganic filler include titanium, silica, talc, kaolin, mica, and diatomaceous earth.

  In addition, the cosmetic composition according to the present invention may contain an active agent for treating fatty skin when used in a foundation. Examples of the active agent include β-lactam derivatives, ciprofloxacin, normalfloxacin, tetracycline and salts thereof, erythromycin and salts thereof, and extracts from plants.

  Furthermore, the cosmetic composition according to the present invention may contain a fatty acid, an emulsion, a silicone oil, a water-soluble polymer, a pigment, an organic additive, and the like as necessary when used in a foundation. Examples of the cosmetic composition include cream, aqueous solution, emulsion, gel, and powder.

  As fatty acids, saturated fatty acids and unsaturated fatty acids and derivatives thereof can be used. For example, saturated fatty acids include caprylic acid, lauric acid, myristic acid, palmitic acid, stearic acid, and mixtures thereof. Examples of unsaturated fatty acids include palmitolic acid, myristoleic acid, oleic acid, and the like, and mixtures thereof, polyunsaturated fatty acids such as linoleic acid, linolenic acid, and erucic acid. As the fatty acid derivative, a hydroxylated or esterified derivative can be used.

  The emulsion is preferably a water-in-oil type. As the oil phase, non-silicone organic oils such as silicone oil, mineral oil, vegetable oil, beeswax, fats and oils, and waxes, or mixtures thereof can be used.

  Examples of the silicone oil include volatile silicone oil and nonvolatile silicone oil. Examples of the water-soluble polymer include polyvinyl alcohol, polyvinyl pyrrolidone, and polyacryl carboxylic acid. Examples of the pigment include iron oxide pigments. Organic additives include wetting agents such as amino acids and urea, fragrances, pigments, preservatives and the like. Examples of the oil-soluble medium include paraffin, polyethylene wax, liquid paraffin, carnauba wax, vegetable oil, beeswax, silicone oil, aliphatic alcohol and the like.

  When used in a foundation, the cosmetic composition according to the present invention has effects such as smoothing the unevenness of the skin and concealing skin defects and dents when applied directly to the skin, and imparts a sense of transparency. Moreover, it exists between the cosmetic material and skin applied on top, and shows adhesiveness to both.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples. The crystallinity, average particle diameter, crystallite size, specific surface area, average pore diameter, porosity, reflection / scattering characteristics of particles, spherulite structure, and the like were measured as follows.

(Crystallinity)
The degree of crystallinity was measured by DSC (differential scanning calorimeter). Specifically, in a nitrogen stream at a flow rate of 40 ml / min, the heat of crystal fusion determined from the area of the endothermic peak at a heating rate of 10 ° C./min and a temperature range of 120 to 230 ° C., and the heat of crystal fusion of a known polyamide It calculated | required from ratio (Formula shown by following formula 1). The heat of fusion of polyamide 6 is R.V. It was set to 45 cal / g according to the description of Vieweg et al., Kunststoffe IV polyamide, page 218, Carl Hanger Verlag, 1966.

(Average particle size)
The average particle size and particle size distribution were measured as an average value of 50000 fine particles using a Coulter Counter (CC). The number average particle size is expressed by the following formula 2, the volume average particle size is expressed by the following formula 3, and the particle size distribution index (PDI) is expressed by the following formula 4.

(Crystallite size)
Using a RGA 2500 rotating cathode X-ray diffractometer RINT2500, using CuKα rays, tube voltage 40 kV, tube current 130 mA, scanning speed 10 ° / min, slit conditions DS (divergence slit) / SS (scattering slit) / RS (Light receiving slit) = Diffraction pattern was obtained in a scanning range of 15 to 40 ° under the condition of 0.5 ° / 0.5 ° / 0.15 mm. From the obtained diffraction pattern, the crystallite size D when the Scherrer constant K was set to 1 was calculated from the Scherrer equation represented by the following formula 5. When there were a plurality of diffraction peaks, the crystallite size was calculated for each peak, and the average value was taken as the crystallite size.

(Specific surface area)
The specific surface area was measured at three points by the BET method using nitrogen adsorption.

(Average pore diameter / porosity)
The average pore diameter was measured with a mercury porosimeter. The measurement range determined the average pore diameter in the range of 0.0036 to 14 μm. The porosity P (porosity) of the porous polyamide fine particles represents the ratio of the volume of the polyamide in one particle to the volume of the space (expressed by the formula shown in the following formula 6). That is, if it is set as the cumulative pore volume (P ₁ ) within the particle, it is expressed by the following equation (7).

From the figure of the cumulative pore volume with respect to the pore diameter, the intra-particle cumulative pore volume is calculated, and the intra-particle porosity is calculated according to the formula shown by the following formula 8. At this time, the density ρ of the porous polyamide fine particles was determined from the crystallinity χ, crystal density ρc, and amorphous density ρa determined by DSC. Here, the crystal density (ρc) of the polyamide 6 was 1.23 cm ³ / g, and the amorphous density (ρa) was 1.09 cm ³ / g.

The degree of porosity (RI) of the porous polyamide fine particles can be represented by the ratio of the specific surface area value Sp ₀ when the spherical particles are assumed to have the same particle diameter and the BET specific surface area Sp in the case of porous fine particles. It is calculated | required by the formula shown by Formula 9 and 10.

(Evaluation of reflection characteristics of particles)
Evaluation of the reflection / scattering characteristics of the particles was performed using Color System Co., Ltd., Color System Co., Ltd., Color System Color Robot III. The particles are uniformly placed on a tape having a thin adhesive layer, and the reflected / scattered light of light incident from the 45 ° direction is detected at a light receiving angle of −85 ° to 85 °, and the Y component in the CIE chromaticity coordinates (visual sense) (Reflectance) was plotted on polar coordinates and evaluated by setting the magnitude of the specular reflection component to -45 °.

(Residual solvent amount in particles)
The amount of residual solvent in the powder after drying was quantified by GC-MS manufactured by JEOL, which was generated by heat extraction at 320 ° C. with a Double Shot Piolaizer manufactured by Frontier Lab.

(Evaluation of spherulite structure)
Whether a particle has a spherulite structure, or a partly deficient spherulite structure (C type, slanted ball structure) and a deficient axial crystal spherulite structure (dumbbell shape) can be determined by scanning type or transmission type. The cross section of the particles was observed with an electron microscope, and it was confirmed that polyamide fibrils were growing radially from the vicinity of the central core. Further, when the particles were observed with a polarizing microscope, it was confirmed whether or not the particles had a bright field even if the polarizer and analyzer were crossed Nicols.

Example 1
After mixing polyamide 6 (manufactured by Ube Industries Co., Ltd .: molecular weight 13,000) with glycerin in a container so that the weight concentration of polyamide is 20% by weight, the temperature of the solution is introduced while introducing nitrogen gas into the system. Was raised, the polyamide started to dissolve at 180 ° C., and this temperature was taken as the phase separation temperature. The temperature was further raised and dissolved with heating until stirring at 200 ° C. to obtain a homogeneous solution. To this solution, 80 ° C. glycerin was added with stirring until 140 ° C. ± 1 ° C., 40 ° C. lower than the phase separation temperature, and further stirred for 20 seconds. After confirming that there was no concentration fluctuation, in a 140 ° C. oil bath Left at rest. As a result, after standing, the solution began to become cloudy after about 15 seconds, and a uniform precipitate of polyamide 6 was obtained without generating any massive precipitate in the container. The obtained precipitate was washed with methanol, dried, and then observed with a scanning electron microscope (SEM). As a result, axial crystal (dumbbell-shaped) porous fine particles as shown in FIG. 1 were observed. The number average particle size was 11.5 μm, the volume average particle size was 16.4 μm, and the PDI was 1.4, which was a relatively uniform particle size. When the cross section was observed with a TEM, it was confirmed that the cross section was dumbbell-shaped spherulites in which nylon fibrils grew mainly in two directions from the center. The specific surface area was 8.4 m ² / g, and the average pore diameter was 14.2 nm. The amount of residual glycerin was 2500 ppm. When the crystallinity of the obtained particles was measured by DSC measurement, the crystallinity of the particles was 51.9% and the crystallite size was 13.9 nm. The result of the light reflection measurement of the sample in which the porous fine particles are uniformly placed on the adhesive tape is shown in FIG. 2 as polar coordinates. In this particle, reflection at an angle of −45 ° was remarkably suppressed, reflection at 0 ° was high, and light scattering characteristics close to a uniform circular shape in all directions were exhibited.

(Comparative Example 1)
Laurolactam (50 g) was added with liquid paraffin (130 mL), and as a dispersion aid, sodium stearate (1 g) was added, heated to a temperature of 160 ° C., sodium (230 mg) and acetylcaprolactam (0.98 mL) were added, and polymerized for 2 hours. After filtration, it was washed with boiling xylene and then vacuum dried to obtain polyamide fine particles.
The obtained polyamide fine particles had a number average particle size of 5.9 μm, a volume average particle size of 7.8 μm, a PDI of 1.32, a porous structure was not observed on the particle surface, and non-porous true spherical particles. there were. Nylon fibrils growing radially from the central core were not observed by TEM observation of the cross section. The specific surface area was 1.1 m ² / g. When the crystallinity of the obtained particles was measured by DSC measurement, the crystallinity was 57%. FIG. 2 shows the result of light reflection measurement of a sample in which the particles are uniformly placed on an adhesive tape in polar coordinates. In this particle, -45 ° reflection of light appeared remarkably, the reflection at 0 ° was low, and the light scattering property was low.

(Comparative Example 2)
Polyamide 6 (molecular weight: 13,000) was added to and dissolved in a solution containing phenol and methanol in a weight ratio of 9: 1 to prepare a polyamide 6 solution having a polyamide 6 concentration of 5% by weight. To this polyamide 6 solution, a mixed solution in which methanol and water were mixed at a mixing ratio of 7: 0.5 was added. The temperature was room temperature. The mixture was allowed to stand for 24 hours to complete the precipitation. Thereafter, the polymer was isolated by centrifugation, and then centrifugal dehydration was performed while applying methanol at 50 ° C. 100 times the amount of fine particles to wash the particles. The obtained particles had a porous structure. When the cross-section was observed with a TEM, it was confirmed that the spherulite had nylon fibrils grown from the center. A SEM image of the particles is shown in FIG. When the particle size distribution of the obtained particles was measured with a Coulter counter, they were relatively uniform particles having a number average particle size of 10.0 μm and a volume average particle size of 13.8 μm. The average pore size was 56.8 nm, the crystallite size was 11.2 nm, PDI 1.4, the specific surface area was 21.4 m ² / g, the porosity index was RI42.1, and the crystallinity was 56%. FIG. 2 shows the result of light reflection measurement of a sample in which the obtained particles are uniformly placed on an adhesive tape. In this particle, the reflection at 0 ° angle is the same as in Example 1, but a slight reflection is seen in the −45 ° angle direction, and it shows an elliptical light scattering characteristic as compared with the particle in Example 1. The light scattering property was inferior.

(Example 2)
Polyamide 6 (manufactured by Ube Industries, Ltd .: molecular weight 13,000) was mixed with ethylene glycol in a container so that the weight concentration of the polyamide was 10% by weight, and then nitrogen gas was introduced into the system, When the temperature was raised, the polyamide started to dissolve at 150 ° C., and this temperature was taken as the phase separation temperature. The temperature was further raised, and the mixture was heated and dissolved with stirring until 180 ° C. to obtain a homogeneous solution. To this solution, ethylene glycol at 40 ° C. was added while stirring until 110 ° C. ± 1 ° C., which was 40 ° C. lower than the phase separation temperature, and further stirred for 20 seconds. After confirming that there was no concentration fluctuation, oil bath at 110 ° C. I left it inside. As a result, after standing, the solution began to become cloudy after about 50 seconds, and a uniform precipitate of polyamide 6 was obtained without generating any massive precipitate in the container. The obtained precipitate was washed several times with methanol, and observed with a scanning electron microscope and the particle size was measured. The SEM image is shown in FIG. As a result, porous substantially slanted (C-shaped) particles having a relatively uniform particle size with a number average particle size of 20.1 μm and a volume average particle size of 23.5 μm were observed. The amount of residual ethylene glycol was 1000 ppm. When the crystallinity of the obtained particles was measured by DSC measurement, the crystallinity of the particles was 52.3%. The crystallite size was 14.3 nm. When the cross section was observed with a TEM, it was confirmed that it was a C-shaped spherulite in which nylon fibrils grew from the center. The specific surface area was 5.1 m ² / g, the average pore diameter was 55 nm, and the PDI was 1.2. This particle also showed high light scattering properties as in Example 1.

(Comparative Example 3)
A polyamide 6 precipitate was obtained by incubating the ethylene glycol solution of the polyamide of Example 2 on a stainless steel vat kept at 75 ° C. for 30 minutes with a liquid film having a thickness of 1.5 mm. The resulting precipitate was washed several times with methanol, and the particle size and SEM observation were performed. Although the particles were agglomerated, a fine porous structure was observed on the surface. The SEM image is shown in FIG. The obtained porous polyamide fine particles had a number average particle size of 9.8 μm, a volume average particle size of 14.0 μm, an average pore size of 19 nm, PDI of 1.43, a crystallite size of 12.6 nm, a specific surface area of 3.0 m ² / g, crystals The degree of conversion was 47.5%. When the cross section was observed by TEM, no growth of nylon fibrils was observed near the center, and only some nylon fibrils were observed near the particle surface. As shown in FIG. 2, reflection was observed in the −45 ° angle direction, reflection at 0 ° angle was also reduced, and it was confirmed that the light scattering property was low.

(Example 3)
(1) Foundation cosmetic composition Using the porous polyamide fine particles obtained in Example 1, component compositions A to G shown in Table 1 were prepared, and these were uniformly mixed to prepare a cream foundation. About the obtained cream foundation, it is very good: 5 points, good: 4 points, normal: 3 points, bad: 2 points, very bad: The average value of the evaluation results of the five-point evaluation of 1 point is shown. By using the porous polyamide fine particles according to this example, a foundation with particularly high evaluation was obtained in terms of adhesion to the skin, tactile sensation after coating, covering power and natural feel of makeup.

(Comparative Examples 4-6)
Using the particles obtained in Comparative Examples 1 to 3, a foundation was prepared in the same manner as in Example 3. According to a questionnaire for 20 healthy adult female monitors for each item, very good: 5 points, good: 4 points , Normal: 3 points, Bad: 2 points, Very bad: 1 point, 5-point evaluation was performed. The results are shown in Table 2 as in Example 3.

Example 4
(2) Production of colored powder of lip cream (2-1) 40 g of porous polyamide fine particles obtained in Example 1 were mixed with 1 g of red No. 106, 5 g of benzyl alcohol, 10 g of N-methyl-2-pyrrolidone and 84 g of water. It was immersed in the prepared aqueous solution and heated to 50 ° C. After 20 minutes, the dyed powder was filtered, washed and dried at 40 ° C. for 24 hours. To 96 g of the obtained powder, it was added to a solution dissolved in 300 g of silicone oil (SH1107C manufactured by Toray Dow Silicone Co., Ltd.), stirred and dried to obtain a colored powder.

(2-2) Preparation of lip balm (1) Paraffin: 15.0 wt%, (2) Candelilla wax: 3.0 wt%, (3) Carnauba wax: 2.0 wt%, (4) Methyl Phenylpolysiloxane: 40.0 wt%, (5) Liquid paraffin: 29.8 wt%, (6) Fragrance: 0.2 wt%, (7) Antioxidant: appropriate amount, (8) Colored powder: 10 0.01% by weight, (1) to (7) were dissolved and mixed at 80 to 85 ° C., then the colored powder of (8) was mixed, poured into a predetermined container, cooled and solidified to obtain a lip balm. Obtained.

(Example 5)
(3) Eyeshadow (1) Talc: 10.0 wt%, (2) Kaolin: 6.0 wt%, (3) Magnesium carbonate: 1.0 wt%, (4) Zinc stearate: 5.0 wt% %, (5) Titanium oxide: 2.0% by weight, (6) Titanium oxide-coated mica: 20.0% by weight, (7) Colored powder prepared in Example 4: 50.0% by weight, (8) Sorbitan sesquioleate: 1.0% by weight, (9) liquid paraffin: 5.0% by weight, (10) fragrance: a small amount, (11) preservative: a small amount, and uniformly (1) to (7) Then, (8) to (11) were added and mixed to obtain an eye shadow.

(Example 6)
(4) Therapeutic cosmetics As an emollient, a cream was prepared in which 10% isohexadecane was supported on the porous polyamide fine particles obtained in Example 1.

  When the cosmetic composition containing the porous polyamide fine particles according to the present invention is applied to human skin, the excellent light scattering property reduces abnormal light reflection (shine) on the skin surface and uniformly scatters the reflected light. By doing so, pores, spots, wrinkles can be concealed, and a natural feeling can be produced. In addition, since it has a porous structure, it effectively absorbs fat and oil components that ooze out from the body and is less likely to lose its shape during use as a cosmetic.

Claims (7)

  A porous polyamide fine particle for a cosmetic composition, comprising a spherulite structure, having a crystallite size of 12 nm or more by wide-angle X-ray analysis and a crystallinity of 50% or more by DSC.   The porous polyamide fine particles for a cosmetic composition according to claim 1, wherein a sphere-equivalent number average particle diameter is 1.0 to 30 µm. 3. A porous polyamide fine particle for a cosmetic composition according to claim 1 or 2, wherein the specific surface area is 0.1 to 80 m < ² > / g.   The porous polyamide fine particles for a cosmetic composition according to any one of claims 1 to 3, wherein the amount of residual polyhydric alcohol when dried powder is less than 10,000 ppm.   5. The porous polyamide fine particles for a cosmetic composition according to claim 4, wherein the residual polyhydric alcohol is ethylene glycol, 1,3 butanediol or glycerin.   A cosmetic composition comprising the porous polyamide fine particles for a cosmetic composition according to any one of claims 1 to 5 and a cosmetic base material.   The cosmetic composition according to claim 6, wherein the porous polyamide fine particles comprise polyamide 6.